1.
Copper sulphate crystals
contain water of crystallization (CuSO4.5H2O). The
crystalline nature and the blue colour of the crystals are due to the water of
crystallization.
2.
When copper sulphate
crystals are heated the water of crystallization is give out.
3.
Anhydrous copper sulphate
is a white amorphous powder.
Hence, copper sulphate crystals on heating turn to
a white powder. 